Category:
Equipment for clarifiers

Radial Scraper

Radial sludge scrapers are intended for sludge removal from the bottom of the primary clarifiers. Sludge scrapers are used to in radial primary clarifiers of the wastewater treatment plants.

The sludge scrapers for clarifiers with internal diameters of 16, 18, 24, 28, 30, 40, 50, 54 m, and non standard diameters can be manufactured using:

  • stainless steel AISI304 or AISI 316 along with polymer materials
  • stainless steel AISI304 or AISI 316 along with aluminium alloy

The sludge scraper is an integral piece of equipment and technological accessory. The main equipment include the bridge, platform, flights with scrapers and the driven trolley.

Scrapers are placed on the flights which are suspended from the rotary platform by means of poles and rods. The scrapers' length and shape are changed according to their proximity to the central pit. The scrapers are provided with rubber aprons that improve their scraping ability.


The central bearing is installed as a rotational bearing assembly. The bridge provides access to the centre of the sludge scraper. The driving trolley is located on the external part of the bridge. It is equipped a variable speed drive to change rotation and speed. As an option, a driving trolley is offered in all wheel drive for reliable operation in winter conditions.

The other end of the bridge is supported by the platform and the central shaft. Metal or plastic flooring, secured with hand rails, is mounted on the bridge.

A variety of accessories can be supplied in addition to the sludge scraper.
Accessories include:
  • clarifier board lane cleaner with electric drive
  • mechanical clarifier tray edge cleaning device with electric drive
  • clarifier water surface floating material collection and removal device

The sludge scraping complex operates in continuous mode. The scraper flights are actuated by the drive trolley. The scraper flights rotate 1 - 3.5 times per hour, depending on clarifier's diameter. Orientated at an angle, the scrapers move the sludge to the pit in the clarifier's center, where the sludge is directed to further dewatering. The sludge scraper sis supplied with a frequency inverter which provides smooth starting and allows the operator to adjust the scraper's rotation and speed.

  • all parts are manufactured from corrosion resistant materials such as stainless steel AISI304 or AISI 316, aluminium alloy and polymers
  • the central swivel mounting performs as the rotation bearing assembly and makes equipment installation and service considerably easier
  • because the driving trolley is all wheel driven, it maintains traction in winter time

The system operates in a fully automatic mode. Alarm systems of the normal operation indication and emergency stops are provided.

It is possible to transfer equipment status data to a higher level automated process control system depending on the client’s requirements.
Parameter Value
Internal diameter of clarifier, mm 16 000...54 000
Clarifier depth, mm 2000...6000
Bridge rotaring frequency, rph 1...3,5
Electric drive: gear-motor, type NORD, cylindrical and conical (1 or 2 pieces)
Wheel diameter, mm 2 x 380 (430)
Power of electric drive 0,37...1,1
Frequency of the current, Hz 50
Voltage 380